PP does not stain anything. What brown stain you see is oxidized
material and it comes off. Malachite Green will stain silicone and
plastics. so IMHO its best to use MG or other coper based type
treatments in a bare tank or a tank you do not mind having a bueish or
green colored sealer or air lines on. This is just about impossible to
remove, but does diminish with time.lots of time......

The brown stain from PP which normally is only going to be at the
water level or on anything that was oxidized, comes right off with a
rinse under water or just normal filtration and is not a
problem........The majority of aquariums are not really all that laden
with organic etc that get oxidized, as compared to natural ponds.



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Put some color in your cheeks...garden naked!